HK1188201A - Electrical purification apparatus having a blocking spacer - Google Patents

Description

Electrical purification device with blocking spacer

Cross Reference to Related Applications

In accordance with 35U.S.C. § 119(e), the present patent application claims priority from U.S. provisional patent application serial No. 61/413,021 entitled "CROSS-FLOW ELECTROCHEMICAL reactions DEVICE AND METHODS OF manual reactions, filed 11/12/2010 and U.S. provisional patent application serial No. 61/510,157 entitled" module CROSS-FLOW ELECTROCHEMICAL reactions DEVICE AND METHODS OF manual reactions, filed 21/7/2011, the entire disclosures OF each OF which are incorporated herein by reference for all purposes.

Technical Field

The present disclosure relates to systems and methods of water treatment, and methods of making systems or devices for water treatment. More particularly, the present disclosure relates to systems and methods for water treatment using electrical purification devices, and methods of manufacturing electrical purification devices for treating water.

Disclosure of Invention

One or more aspects of the present disclosure relate to a method of preparing a first cell stack for an electrical purification apparatus. The method comprises the following steps: the first anion exchange membrane is secured to the first cation exchange membrane at a first portion of the perimeter of the first anion exchange membrane and the first cation exchange membrane to form a first chamber having a first fluid flow passage. The method further comprises the following steps: securing a second anion exchange membrane to the first cation exchange membrane at a second portion of the perimeter of the first cation exchange membrane and a first portion of the perimeter of the second anion exchange membrane to form a second chamber having second fluid flow channels in a different direction than the first fluid flow channels. Each of the first and second compartments may be constructed and arranged to provide a fluid contact of greater than 85% of the respective surface area of the first cation exchange membrane, the first anion exchange membrane, and the second cation exchange membrane.

Other aspects of the present disclosure relate to a method for preparing a cell stack of an electrical purification apparatus. The method may include forming a first chamber by securing a first cation exchange membrane to a first anion exchange membrane at a first portion of a perimeter of the first anion exchange membrane and the first cation exchange membrane to provide a first spacer assembly having a first spacer disposed between the first cation exchange membrane and the first anion exchange membrane. The method may further include forming a second chamber by securing a second anion exchange membrane to a second cation exchange membrane at a first portion of a perimeter of the second anion exchange membrane and the second cation exchange membrane to provide a second spacer assembly having a second spacer disposed between the second anion exchange membrane and the second cation exchange membrane. The method may further include forming a third chamber by securing the first spacer assembly to the second spacer assembly at a second portion of the perimeter of the first cation exchange membrane and at a portion of the perimeter of the second anion exchange membrane to provide a stack assembly having spacers disposed between the first spacer assembly and the second spacer assembly. Each of the first and second chambers may be constructed and arranged to provide a fluid flow direction in a direction different from a fluid flow direction within the third chamber.

Other aspects of the present disclosure may provide an electrical purification apparatus including a cell stack. The cell stack can include a first chamber including a first cation exchange membrane and a first anion exchange membrane. The first chamber may be constructed and arranged to provide direct fluid flow in a first direction between the first cation exchange membrane and the first anion exchange membrane. The cell stack may further include a second chamber, which may include a first anion exchange membrane and a second cation exchange membrane, to provide direct fluid flow in a second direction between the first anion exchange membrane and the second cation exchange membrane. Each of the first and second compartments is constructed and arranged to provide a fluid contact of greater than 85% of the surface area of the first cation exchange membrane, the first anion exchange membrane, and the second cation exchange membrane.

Other aspects of the present disclosure relate to a cell stack for an electrical purification apparatus. The cell stack may include a plurality of alternating ion depleting compartments and ion concentrating compartments. Each ion depletion chamber may have an inlet and an outlet providing a flow of diluting fluid in a first direction. Each ion concentrating chamber may have an inlet and an outlet that provide a concentrated fluid flow in a second direction different from the first direction. The cell stack may also include a blocking spacer positioned within the cell stack. The blocking spacer may be constructed and arranged to redirect at least one of the dilute fluid flow and the concentrated fluid flow through the cell stack.

Other aspects of the present disclosure relate to an electrical purification apparatus. The electrical purification apparatus includes a cell stack that includes alternating ion diluting compartments and ion concentrating compartments. Each ion dilution chamber may be constructed and arranged to provide a fluid flow in a first direction. Each ion concentrating chamber may be constructed and arranged to provide fluid flow in a second direction different from the first direction. The electrical purification apparatus may include a first electrode adjacent to the anion exchange membrane at a first end of the cell stack. The electrical purification apparatus may also include a second electrode located at a second end of the cell stack adjacent the cathode exchange membrane. The blocking spacer may be located in the cell stack and constructed and arranged to redirect at least one of the dilute fluid stream and the concentrated fluid stream through the electrical purification apparatus and prevent a direct current path between the first electrode and the second electrode.

In other aspects of the present disclosure, a method of providing a source of potable water is provided. The method may include providing an electrical purification apparatus including a cell stack. The cell stack may include alternating ion diluting compartments and ion concentrating compartments. Each ion dilution chamber may be constructed and arranged to provide a fluid flow in a first direction. Each ion concentrating chamber may be constructed and arranged to provide fluid flow in a second direction different from the first direction. Each ion concentrating and diluting compartment may be constructed and arranged to provide fluid contact of greater than 85% of the respective surface area of the alternating ion diluting and diluting compartments. The method may further comprise fluidly connecting a feed stream of seawater containing about 35,000 ppm total dissolved solids to an inlet of the electrical purification apparatus. The method may further comprise fluidly connecting an outlet of the electrical purification apparatus to a drinking point.

Drawings

The figures are not intended to be drawn to scale. In the drawings, like numerals refer to like or nearly like parts throughout the several views. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

fig. 1 is a schematic view of a portion of an electrical purification apparatus according to one or more embodiments of the present disclosure;

fig. 2 is a schematic view of a portion of an electrical purification apparatus according to one or more embodiments of the present disclosure;

fig. 3 is a schematic view of a portion of an electrical purification apparatus according to one or more embodiments of the present disclosure;

fig. 4 is a schematic view of a portion of an electrical purification apparatus according to one or more embodiments of the present disclosure;

FIG. 5 is a schematic side view of a portion of an electrodeionization device comprising a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

FIG. 6 is a schematic side view of a portion of an electrodeionization device comprising a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

FIG. 7 is a schematic side view of a portion of an electrodeionization device comprising a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 8 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 9 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 10 is a schematic view of one or more embodiments of a method of securing a membrane cell stack within a housing according to the present disclosure;

fig. 11 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 12 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 13 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 14 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 15 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 16 is a schematic view of a method of securing a membrane cell stack within a housing according to one or more embodiments of the present disclosure;

fig. 17 is a schematic view of a multi-pass electrical purification apparatus according to one or more embodiments of the present disclosure;

figure 18 is a schematic view of a blocking spacer according to one or more embodiments of the present disclosure;

FIG. 19 is a schematic view of a spacer assembly and blocking spacers therebetween according to one or more embodiments of the present disclosure;

fig. 20 is a schematic view of a portion of an electrical purification apparatus including a cell stack located within a housing, according to one or more embodiments of the present disclosure;

figure 21 is a schematic view of a blocking spacer according to one or more embodiments of the present disclosure;

fig. 22 is a schematic view of a portion of an electrical purification apparatus including a cell stack located within a housing, according to one or more embodiments of the present disclosure;

fig. 23A and 23B are schematic diagrams of a portion of an electrical purification apparatus including a cell stack within a housing, according to one or more embodiments of the present disclosure;

fig. 24A and 24B are schematic views of a portion of an electrical purification apparatus including a first modular unit, a second modular unit, and a blocking spacer therebetween, in accordance with one or more embodiments of the present disclosure;

figure 25 is a schematic view of a blocking spacer according to one or more embodiments of the present disclosure;

FIG. 26 is a schematic view of a spacer assembly according to one or more embodiments of the present disclosure;

FIG. 27 is a schematic view of a cell stack according to one or more embodiments of the present disclosure;

FIG. 28 is a schematic view of a cell stack according to one or more embodiments of the present disclosure;

FIG. 29 is a schematic view of a cell stack according to one or more embodiments of the present disclosure;

FIG. 30 is a schematic view of a spacer according to one or more embodiments of the present disclosure;

FIG. 31 is a schematic exploded view of a cell stack through membranes and spacers according to one or more embodiments of the present disclosure;

figure 32 is a schematic cross-sectional view and detail view of a partially assembled cell stack according to one or more embodiments of the present disclosure;

FIG. 33 is a schematic view of a portion of an assembled stack according to one or more embodiments of the present disclosure;

FIG. 34 is a schematic view of an overmolded spacer in accordance with one or more embodiments of the present disclosure;

fig. 35 is a schematic cross-sectional view of a cell stack according to one or more embodiments of the present disclosure;

figure 36 is a schematic cross-sectional view of a cell stack according to one or more embodiments of the present disclosure;

FIG. 37 is a schematic top view of a spacer according to one or more embodiments of the present disclosure;

FIGS. 38A and 38B are schematic views of details of a spacer according to one or more embodiments of the present disclosure; FIG. 38B is a cross-section taken along line B-B of FIG. 38A;

FIG. 39 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention;

FIG. 40 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention;

FIG. 41 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention;

FIG. 42 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention;

FIG. 43 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention; and is

FIG. 44 is a schematic view of a stack of spacers and membranes according to one or more embodiments of the invention.

At least some of the figures may depict membranes, spacers, cell stacks, and enclosures in particular configurations and geometries. However, the present disclosure is not limited to these particular configurations and geometries. For example, the housing may have any suitable geometry such that one or more membrane cell stacks or modular units may be secured within the housing. For example, the housing may be cylindrical, polygonal, square, or rectangular. In the case of membrane cell stacks and modular units, any suitable geometry is acceptable, as long as the cell stack or modular unit can be secured to the housing. For example, the membrane or spacer may have a rectangular shape. In some embodiments, no housing may be required. The geometry of the membranes and spacers may be any suitable geometry such that the membranes and spacers may be secured within the cell stack. In certain embodiments, a particular number of corners or vertices on the cell stack may be desired. For example, it may be desirable to have three or more corners or vertices to secure the cell stack to the housing. In certain embodiments, the geometry of any of the housing, cell stack, membrane, and spacer can be selected to accommodate the operating parameters of the electrical purification apparatus. For example, the spacer may be asymmetric to accommodate the difference in flow rate between the dilute and concentrate streams.

Detailed Description

Devices for purifying fluids using electric fields are commonly used for the treatment of water and other liquids containing dissolved ions. Two types of devices that treat water in this manner are electrodeionization devices and electrodialysis devices.

Electrodeionization (EDI) is a method of removing or at least reducing one or more ionized or ionizable species from water using an electrically active medium and an electrical potential to affect ion transport. Electroactive media are commonly used to alternately collect and release ionic and/or ionizable species, and in some cases utilize ionic or electronic substitution mechanisms to facilitate ion transport, which may be continuous. The EDI device may include electrochemically active media that is permanently or temporarily charged, and may be operated in batch, intermittently, continuously, and/or even in reversed polarity mode. The EDI device may operate to facilitate one or more electrochemical reactions specifically designed to achieve or enhance performance. Furthermore, such electrochemical devices may comprise electroactive membranes, such as semi-permeable or permselective ion exchange membranes or bipolar membranes. Continuous Electrodeionization (CEDI) devices are known to those skilled in the art as electrodeionization devices that operate in a manner that enables continuous water purification while continuously replenishing ion exchange material. CEDI technology may include methods such as continuous deionization, packed cell electrodialysis, or electrodialysis (electrodialysis). Under controlled voltage and salinity conditions, in a CEDI system, water molecules can be split to produce hydrogen or hydronium ions or species and hydroxide or hydroxyl ions or species, which can regenerate the ion exchange media in the device thereby facilitating release of captured species therefrom. In this way, the aqueous stream to be treated can be purified continuously without chemical replenishment of the ion exchange resin.

Electrodialysis (ED) devices work on a similar principle to CEDI, except that they typically do not contain an electroactive medium between the membranes. For low salinity feed water, the resistance increases due to the lack of electroactive media, thus hindering the operation of electrodialysis. Also, because electrodialysis operation on high salinity feed water can result in increased current consumption, electrodialysis devices have been most effectively used for moderate salinity source water to date. In systems based on electrodialysis, the separation of water is not sufficient because there is no electroactive medium and operation in this case is generally avoided.

In CEDI and ED devices, a plurality of adjacent cells or chambers are typically separated by a selectively permeable membrane that allows the passage of positively or negatively charged species but typically does not allow both species to pass through at the same time. In such devices, the diluting or depleting compartments are typically separated by concentrating compartments. As the water flows through the depleting compartments, ions and other charged species are generally drawn into the concentrating compartments under the influence of an electric field (e.g., a dc electric field). Positively charged species are attracted to the cathode, typically at one end of a stack of a plurality of depleting compartments and concentrating compartments, and negatively charged species are similarly attracted to the anode of such devices, typically at the opposite end of the stack of compartments. These electrodes are typically housed in an electrolyte chamber, which is typically partially isolated from fluid communication with the depleting and/or concentrating chambers. Once in the concentration chamber, the charged species are typically captured by a barrier of selectively permeable membranes that at least partially define the concentration chamber. For example, cation selective membranes generally prevent further movement of anions out of the concentrating compartment toward the cathode. Once captured in the concentration chamber, the captured charged species may be removed in the concentration stream.

In CEDI and ED devices, a direct current electric field is typically applied to the cell from a voltage and current source applied to the electrodes (anode or positive electrode, and cathode or negative electrode). The voltage and current sources (collectively "power sources") themselves may be powered by a variety of means (e.g., an ac power source) or by a power source derived from, for example, solar, wind, or wave energy. Electrochemical half-cell reactions occur at the electrode/liquid interface that initiate and/or facilitate ion transport through the membrane and the chamber. The salt concentration in the dedicated compartment housing the electrode assembly can be used to control to some extent the specific electrochemical reactions occurring at the electrodes/interfaces. For example, a feed having a high sodium chloride content delivered to the anolyte compartment will tend to produce chlorine gas and hydrogen ions, while such a feed delivered to the catholyte compartment will tend to produce hydrogen gas and hydroxide ions. Generally, hydrogen ions generated at the anode compartment will associate with free anions (e.g., chloride ions) to maintain electrical neutrality and form a hydrochloric acid solution, and similarly, hydroxide ions generated at the cathode compartment will associate with free ions (e.g., sodium) to maintain electrical neutrality and form a sodium hydroxide solution. The reaction products of the electrode compartment, such as the chlorine and sodium hydroxide produced, can be used in the process as desired for disinfection purposes, for membrane cleaning and decontamination purposes, and for pH adjustment purposes.

The plate and frame and spiral wound design have been used in various types of electrochemical deionization devices including, but not limited to, Electrodialysis (ED) and Electrodeionization (EDI) devices. Commercially available electrodialysis devices are typically of a plate and frame design, while electrodeionization devices can be both of a plate and frame configuration and a spiral configuration.

The present invention relates to a device that can electrically purify a fluid contained within a housing, and methods of making and using the same. The liquid or other fluid to be purified enters the purification apparatus or device and is treated under the influence of an electric field to produce an ion depleted liquid. Nuclides from the incoming liquid are collected to produce an ion-concentrated liquid. The components of the electrical purification apparatus (which may also be referred to as an electrochemical separation system or electrochemical separation apparatus) may be assembled using various techniques to achieve optimal operation of the apparatus.

In some embodiments of the present disclosure, a method of affixing or bonding ion exchange membranes (and optionally spacers) to make a membrane cell stack for an electrical purification apparatus is provided. The method can provide for immobilization of a plurality of anion exchange membranes and cation exchange membranes for an electrical purification apparatus, such as a cross-flow Electrodialysis (ED) apparatus.

In certain embodiments of the present disclosure, a first cell stack method for preparing a device for electrical purification is provided. The method may include securing the first ion exchange membrane to the second ion exchange membrane. The spacer may be positioned between the first ion exchange membrane and the second ion exchange membrane to form a spacer assembly. When used in an electrical purification apparatus, this spacer assembly defines a first chamber that can allow fluid flow. The multiple layers of ion exchange membranes can be secured to one another to provide a series of chambers. In some embodiments, multiple spacer assemblies may be manufactured and may be secured to one another. A spacer may be located between each spacer assembly. As such, the series of chambers for the electrical purification apparatus are configured to allow fluid flow in one or more directions within each chamber.

Spacers, which may be located within the chambers, may provide structure to and define the chambers and, in some instances, may help direct fluid flow through the chambers. The spacer may be made of a polymeric material or other material that enables the desired structure and fluid flow within the chamber. In certain embodiments, the spacer may be constructed and arranged to redirect or redistribute the fluid flow within the chamber. In some examples, the spacer may include a mesh or screen material that provides structure and allows for a desired fluid flow through the chamber.

According to one or more embodiments, the efficiency of an electrochemical separation system may be improved. Current loss is one possible cause of inefficiency. In some embodiments (e.g., those involving cross-current designs), the possibility of current leakage may be addressed. Current efficiency may be defined as the percentage of current available to move ions out of the dilute stream and into the concentrate stream. Various causes of current inefficiency may exist in electrochemical separation systems or electrical purification devices. One possible cause of inefficiency may involve current bypassing the cell pair (adjacent pair of concentrating and diluting compartments) by flowing through the diluting and concentrating inlet and outlet manifolds. The open inlet and outlet manifolds may be in direct fluid communication with the flow chamber and may reduce pressure drop in each flow passage. A portion of the current flowing from one electrode to the other may bypass the stack of cell pairs by flowing through the open area. This bypass current reduces current efficiency and increases power consumption. Another possible cause of inefficiency may involve the passage of ions from the concentrate stream into the dilute stream due to imperfect permselectivity of the ion exchange membrane. In some embodiments, techniques associated with sealing and potting of membranes and screens within devices may help reduce current leakage.

In one or more embodiments, a bypass path through the stack may be operated to facilitate current flow through the cell stack along a direct path, thereby increasing current efficiency. In some embodiments, the electrochemical separation device or electrical purification device may be constructed and arranged such that the one or more bypass paths are more tortuous than the direct path through the cell stack. In at least certain embodiments, the electrochemical separation device or electrical purification device may be constructed and arranged such that the one or more bypass paths have a higher electrical resistance than the direct path through the cell stack. In some embodiments involving modular systems, individual modular units may be configured to improve current efficiency. The modular units may be constructed and arranged to provide a current bypass path that will help improve current efficiency. In non-limiting embodiments, the modular units may include a manifold system and/or a flow distribution system configured to improve current efficiency. In at least some embodiments, the frame surrounding the cell stack in the electrochemical separation unit can be constructed and arranged to provide a predetermined current bypass path. In some embodiments, facilitating the formation of a multi-pass flow configuration within an electrochemical separation device may help reduce current leakage. In at least some non-limiting embodiments, barrier membranes or spacers may be inserted between the modular units to direct the dilute and/or concentrate streams into a multi-pass flow configuration to improve current efficiency. In some embodiments, a current efficiency of at least about 60% may be achieved. In other embodiments, a current efficiency of at least about 70% may be achieved. In other embodiments, a current efficiency of at least about 80% may be achieved. In at least some embodiments, a current efficiency of at least about 85% can be achieved.

The spacer may be constructed and arranged to redirect at least one of fluid flow and electrical current to improve current efficiency. The spacer may also be constructed and arranged to create multiple fluid flow stages in the electrical purification apparatus. The spacer may comprise a solid portion to redirect the fluid flow in a particular direction. The solid portion may also redirect current flow in a particular direction and prevent a direct path between the anode and cathode in the electrical purification apparatus. The spacer including the solid portion may be referred to as a blocking spacer. The blocking spacer may be located within the cell stack or may be located between the first cell stack or first modular unit and the second cell stack or second modular unit.

In some embodiments, the plurality of ion exchange membranes secured to each other may be alternately a cation exchange membrane and an anion exchange membrane to provide a series of ion diluting compartments and ion concentrating compartments.

The geometry of the membranes may be any suitable geometry such that the membranes may be secured within a cell stack. In certain embodiments, it is desirable to have a certain number of corners or vertices on the cell stack in order to properly secure the cell stack within the housing. In certain embodiments, a particular membrane may have a different geometry than other membranes in the cell stack. The geometry of the membrane may be selected to help achieve at least one of: securing membranes to each other, securing spacers within the cell stack, securing membranes within the modular unit, securing membranes within a support structure, securing a set of membranes (e.g., the cell stack) to the housing, and securing the modular unit into the housing.

The membrane, spacer and spacer assembly may be secured at a portion of the perimeter or edge of the membrane, spacer or spacer assembly. A portion of the perimeter may be a continuous or discontinuous length of membrane, spacer, or spacer assembly. The portion of the perimeter selected to secure the membrane, spacer or spacer assembly may provide a boundary or boundary to direct fluid flow in a predetermined direction.

In certain embodiments, a method of preparing a cell stack may include securing a first anion exchange membrane to a first cation exchange membrane at a first portion of a perimeter of the first anion exchange membrane and the first cation exchange membrane to form a first chamber having a first fluid flow channel. The method may further include securing a second anion exchange membrane to the first cation exchange membrane at a second portion of the perimeter of the first cation exchange membrane and a first portion of the perimeter of the second anion exchange membrane to form a second chamber having second fluid flow channels in a different direction than the first fluid flow channels.

The first fluid flow channel and the second fluid flow channel may be selected and provided by portions of the periphery of the ion exchange membrane that are fixed to each other. Taking the first fluid flow channel as the direction extending along the 0 ° axis, the second fluid flow channel may extend in a direction of any angle greater than 0 ° and less than 360 °. In certain embodiments of the present disclosure, the second fluid flow channel may extend in a direction at a 90 ° angle or perpendicular to the first fluid flow channel. In other embodiments, the second fluid flow passage may extend in a direction that is 180 ° from the first fluid flow passage. In another embodiment, the first fluid flow channel may extend in the 0 ° direction. The second fluid flow passages may extend in a direction of 60 deg. and the third fluid flow passages may extend in a direction of 120 deg.. The fourth fluid flow passage may extend in the direction of 0 °.

If additional ion exchange membranes are secured to the cell stack to provide additional chambers, the fluid flow channels in these additional chambers may be the same as or different from the first fluid flow channels and the second fluid flow channels. In certain embodiments, the fluid flow path in each chamber alternates between a first fluid flow path and a second fluid flow path. For example, the first fluid flow passage in the first chamber may extend in the direction of 0 °. The second fluid flow passage in the second chamber may extend in a 90 ° direction and the third fluid flow passage in the third chamber may extend in a 0 ° direction. In some examples, a first fluid flow channel extending in a first direction and a second fluid flow channel extending in a second direction may be referred to as cross-flow electrical purification.

In other embodiments, the fluid flow passages within each chamber alternate between the first fluid flow passage, the second fluid flow passage, and the third fluid flow passage in succession. For example, the first fluid flow channel in the first chamber may extend in the direction of 0 °. The second fluid flow passage in the second chamber may extend in a direction of 30 deg. and the third fluid flow passage in the third chamber may extend in a direction of 90 deg.. The fourth fluid flow passage in the fourth chamber may extend in the 0 ° direction. In another embodiment, the first fluid flow passage within the first chamber may extend in a direction of 0 °. The second fluid flow passage in the second chamber may extend in a direction of 60 deg. and the third fluid flow passage in the third chamber may extend in a direction of 120 deg.. The fourth fluid flow passage in the fourth chamber may extend in the 0 ° direction.

In certain embodiments of the present disclosure, the flow rate within the chamber may be adjusted, redistributed, or redirected, thereby providing greater contact of the fluid with the membrane surface within the chamber. The chamber may be constructed and arranged to redistribute fluid flow within the chamber. The chamber may have obstructions, tabs, protrusions, flanges, or baffles that may provide a structure to redistribute flow through the chamber, as will be described further below. In certain embodiments, the obstruction, protrusion, projection, flange, or baffle may be referred to as a flow redistributor.

Each chamber in the cell stack of the electrical purification apparatus may be constructed and arranged to provide a predetermined percentage of the surface area or membrane utilization for fluid contact. It has been found that greater membrane utilization provides greater efficiency in the operation of an electrical purification apparatus. Advantages of achieving greater membrane utilization may include: reduce energy consumption, reduce the occupied area of the device, reduce the number of strokes of the device and improve the quality of product water. In certain embodiments, the achievable membrane utilization is greater than 65%. In other embodiments, the achievable membrane utilization is greater than 75%. In certain other embodiments, the achievable membrane utilization may be greater than 85%. The membrane utilization rate may depend at least in part on the method used to secure the membranes to one another and the design of the spacer. In order to obtain a predetermined membrane utilization, suitable fastening techniques and components may be selected so as to achieve a reliable and robust seal that allows optimal operation of the electrical purification apparatus without leakage within the apparatus, while maintaining a large surface area of the membrane available for use in the process.

The sealing may be achieved by any suitable means for ensuring engagement between the membranes, thereby providing a desired fluid flow path through the chamber defined by the membranes. For example, sealing may be accomplished with adhesives, thermal bonding, such as via laser or ultrasonic welding, or by mating or interlocking, for example, using male and female features on adjacent films and/or spacers. In some instances, to manufacture a membrane cell stack, a plurality of spacer assemblies are manufactured and the spacer assemblies are bonded or secured together with an adhesive at some portion of the periphery of the spacer assemblies. The spacer is located between the spacer assemblies that are secured together. In some examples, the spacer assemblies may be secured to one another at a portion of the perimeter of each spacer assembly, thereby providing a plurality of chambers having at least two fluid flow channels. For example, the spacer assembly may be secured to one another to provide a first chamber having fluid flow passages in a first direction and a second chamber having fluid flow passages in a second direction. Instead of adhesives, thermal bonding or mechanical interlocking features may be used to provide the chambers.

In some embodiments of the present disclosure, a method of making a cell stack of an electrical purification apparatus includes forming a chamber. The first chamber may be formed by fixing ion exchange membranes to each other to provide a first spacer assembly having a first spacer disposed between the ion exchange membranes. For example, a first cation exchange membrane may be secured to a first anion exchange membrane at a first portion of the perimeter of the first cation exchange membrane and the first anion exchange membrane to provide a first spacer assembly having a first spacer disposed between the first cation exchange membrane and the first anion exchange membrane.

The second chamber may be formed by fixing the ion exchange membranes to each other to provide a second spacer assembly having a second spacer disposed between the ion exchange membranes. For example, a second anion exchange membrane may be secured to a second cation exchange membrane at a first portion of the perimeter of the second cation exchange membrane and the second anion exchange membrane, thereby providing a second spacer assembly having a second spacer disposed between the second anion exchange membrane and the second cation exchange membrane.

A third chamber may be formed between the first and second chambers by securing the first spacer assembly to the second spacer assembly with the spacer between the two assemblies. For example, a first spacer assembly may be secured to a second spacer assembly at a second portion of the perimeter of the first cation exchange membrane and at a portion of the perimeter of the second anion exchange membrane, thereby providing a stack assembly having spacers disposed between the first spacer assembly and the second spacer assembly.

Each of the first and second chambers may be constructed and arranged to provide a fluid flow direction that is different from a fluid flow direction within the third chamber. For example, the fluid flow within the third chamber may extend in the direction of the 0 ° axis. The fluid flow within the first chamber may extend in a 30 ° direction and the fluid flow within the second chamber may extend over the same angle (30 °) as the first chamber or another angle (e.g. 120 °). In another example, the fluid flow path within the first chamber may extend in a direction of 0 °. The fluid flow passages in the third chamber may extend in the 60 ° direction and the fluid flow passages in the second chamber may extend in the 120 ° direction. The fluid flow passage in the fourth chamber may extend in the 0 ° direction.

The method may further comprise securing the assembled cell stack within a housing.

In accordance with one or more embodiments, an electrochemical separation system or electrical purification apparatus may be modular. Each modular unit may generally function as a sub-block of the overall electrochemical separation system. The modular unit may include any desired number of cell pairs. In some embodiments, the number of well pairs per modular unit depends on the total number of wells and strokes in the separation device. It also depends on the number of cell pairs that can be thermally bonded and potted in a frame with an acceptable failure rate when testing for cross-leaks and other performance criteria. The number may be based on statistical analysis of the manufacturing process and may increase when process control improves. In some non-limiting embodiments, a modular unit may include about 50 pool pairs. The modular units can be assembled separately and tested for quality control, e.g., for leaks, separation performance, and pressure drop, before incorporation into a larger system. In some embodiments, the cell stack may be mounted within a frame as a modular unit that can be tested independently. A plurality of modular units can then be assembled together to provide a total projected number of cell pairs in the electrochemical separation device. In some embodiments, the method of assembly may generally comprise: the first modular unit is placed on the second modular unit, the third modular unit is placed on the first and second modular units, and the process is repeated to obtain a desired number of the plurality of modular units. In some embodiments, the assembly or individual modular units may be inserted into the pressure vessel for operation. By placing barrier membranes and/or spacers between or within modular units, a multi-pass flow configuration may be formed. The modular approach may improve manufacturability in terms of time and cost savings. Modularity may also facilitate system maintenance by allowing individual modular units to be diagnosed, isolated, removed, and replaced. The individual modular units may include manifolds and flow distribution systems for facilitating the electrochemical separation process. The individual modular units may be in fluid communication with each other, and with a central manifold and other systems associated with the overall electrochemical separation process.

The cell stack may be secured within a frame or support structure that includes an inlet manifold and an outlet manifold to provide a modular unit. This modular unit can then be secured within the housing. The modular unit may also include bracket assemblies or corner brackets that may secure the modular unit to the housing. The second modular unit may be secured within the housing. One or more additional modular units may also be secured within the housing. In certain embodiments of the present disclosure, a blocking spacer may be positioned between a first modular unit and a second modular unit.

The flow redistributors may be present within one or more of the compartments of the cell stack. In assembling the cell stack, the first portion of the perimeter of the ion exchange membranes in the cell stack may be constructed and arranged to interlock with the first portion of the perimeter of the adjacent ion exchange membranes. In certain examples, a first portion of the perimeter of a first spacer within a cell stack can be constructed and arranged to interlock with a first portion of the perimeter of an adjacent spacer.

In some embodiments of the present disclosure, an electrical purification apparatus is provided that includes a cell stack. The electrical purification apparatus may include a first chamber comprising ion exchange membranes and may be constructed and arranged to provide direct fluid flow between the ion exchange membranes in a first direction. The electrical purification apparatus may also include a second chamber comprising an ion exchange membrane and may be constructed and arranged to provide direct fluid flow in a second direction. Each of the first and second chambers may be constructed and arranged to provide a predetermined percentage of surface area or membrane utilization for fluid contact. In certain embodiments, the achievable membrane utilization is greater than 65%. In other embodiments, the achievable membrane utilization is greater than 75%. In certain other embodiments, the achievable membrane utilization may be greater than 85%. The membrane utilization rate may depend at least in part on the method used to secure the membranes to one another and the design of the spacer. In order to obtain a predetermined membrane utilization, appropriate fixation techniques and components may be selected in order to achieve a reliable and robust seal that allows optimal operation of the electrical purification apparatus without leakage within the apparatus, while maintaining a large surface area of the membrane for use in the process.

For example, an electrical purification apparatus may be provided that includes a cell stack. The electrical purification apparatus can include a first chamber comprising a first cation exchange membrane and a first anion exchange membrane; the first chamber is constructed and arranged to provide direct fluid flow between the first cation exchange membrane and the first anion exchange membrane in a first direction. The apparatus may further comprise a second chamber comprising the first anion exchange membrane and the second cation exchange membrane to provide a direct fluid flow between the first anion exchange membrane and the second cation exchange membrane in a second direction. Each of the first and second compartments may be constructed and arranged to provide a predetermined membrane utilization, such as a fluid contact greater than 85% of the surface area of the first cation exchange membrane, the first anion exchange membrane, and the second cation exchange membrane. At least one of the first chamber and the second chamber may include a spacer, which may be a blocking spacer.

The configuration and arrangement of the chambers may be utilized to select and provide direct fluid flow in the first and second directions. Using the first fluid flow direction as the direction extending along the 0 ° axis, the second fluid flow direction may extend in a direction of any angle greater than zero degrees and less than 360 °. In certain embodiments of the present disclosure, the second fluid flow direction may be at an angle of 90 ° or perpendicular to the first fluid flow direction. In other embodiments, the second fluid flow direction may be in a direction at an angle of 80 ° to the first fluid flow direction. If additional ion exchange membranes are secured to the cell stack to provide additional chambers, the direction of fluid flow in these additional chambers may be the same or different than the first and second fluid flow directions. In certain embodiments, the direction of fluid flow within each chamber alternates between a first fluid flow direction and a second fluid flow direction. For example, the first fluid flow direction may extend in the direction of 0 °. The second fluid flow direction may extend over an angle of 90 ° and the third fluid flow direction in the third chamber may extend in the direction of 0 °.

An electrical purification apparatus comprising a cell stack may further comprise a housing enclosing the cell stack, at least a portion of the perimeter of the cell stack being secured to the housing. A frame may be positioned between the housing and the cell stack to provide a first modular unit within the housing. The flow redistributors may be present in one or more of the compartments of the cell stack. At least one of the chambers may be constructed and arranged to provide flow reversal within the chamber.

In some embodiments of the present disclosure, a cell stack for an electrical purification apparatus is provided. The cell stack may provide a plurality of alternating ion depleting and ion concentrating compartments. Each ion depletion chamber may have an inlet and an outlet providing a flow of diluting fluid in a first direction. Each ion concentrating chamber may have an inlet and an outlet providing a concentrated fluid flow in a second direction different from the first direction. The spacer may be located within the cell stack. The spacer may provide structure to and define the chamber, and may help direct fluid flow through the chamber in some instances. The spacer may be a blocking spacer that may be constructed and arranged to redirect at least one of fluid and electrical current through the cell stack. As described above, the blocking spacer may reduce or prevent current inefficiencies in the electrical purification apparatus.

In some embodiments of the present disclosure, an electrical purification apparatus is provided. The apparatus may include a cell stack including alternating ion diluting compartments and ion concentrating compartments. Each ion dilution chamber may be constructed and arranged to provide a fluid flow in a first direction. Each ion concentrating chamber may be constructed and arranged to provide fluid flow in a second direction different from the first direction. The electrical purification apparatus may also include a first electrode adjacent the first ion exchange membrane at a first end of the cell stack and a second electrode adjacent the second ion exchange membrane at a second end of the cell stack. Each of the first ion exchange membrane and the second ion exchange membrane may be an anion exchange membrane or a cation exchange membrane. For example, the first ion exchange membrane may be an anion exchange membrane and the second ion exchange membrane may be a cation exchange membrane. The device may also include a blocking spacer positioned within the cell stack and constructed and arranged to redirect at least one of the dilute fluid stream and the concentrated fluid stream through the electrical purification device and prevent a direct current path between the first electrode and the second electrode. As described above, the blocking spacer may be constructed and arranged to reduce current inefficiencies in the electrical purification apparatus.

The cell stack for the electrical purification apparatus may be enclosed in a housing, with at least a portion of the perimeter of the cell stack being secured to the housing. A frame may be positioned between the housing and the cell stack to provide a first modular unit within the housing. The second modular unit may also be secured within the housing. A blocking spacer may also be located between the first modular unit and the second modular unit. The flow redistributors may be present in one or more of the compartments of the cell stack. At least one of the chambers is constructed and arranged to provide flow reversal within the chamber. A bracket assembly may be positioned between the frame and the housing to provide support for the modular units and to secure the modular units within the housing.

In certain embodiments of the present disclosure, a portion of the perimeter of the spacer or ion exchange membrane in the cell stack may be treated or coated with a material to provide enhanced secure adhesion to the securing material (e.g., adhesive) and components of the cell stack. A sealing band may be provided on the spacer, the membrane, or both to provide a continuous surface on which an adhesive may be coated to join ion exchange membranes, such as anion and cation exchange membranes. These sealing bands may also provide support for the perimeter of the membrane. The sealing strip prevents or reduces wetting of the adhesive or wicking of the adhesive, thereby enabling less adhesive to be used to secure the spacer and membrane together. The sealing tape may also help to achieve greater film utilization with less adhesive. In some examples, the sealing tape may be applied to the spacer by injection molding, compression molding, coating, or the like.

FIG. 1 shows a spacer assembly 10 including a cation exchange membrane 100, a spacer 104, and an anion exchange membrane 102. The spacer 104 (which may be a mesh spacer) may allow for the application of an adhesive 106. The films may be sealed along the two opposing edges using an adhesive or using a thermal bonding technique (e.g., laser, vibration, or ultrasonic welding). A wide range of adhesives are available for the film side seam, including epoxy resins with aliphatic, cycloaliphatic, and aromatic amine curing agents and polyurethanes, as will be described in more detail below. When applying the adhesive in the glue line of the film pool, it is advantageous if the adhesive remains mostly on the intended glue line. If the viscosity is too low, the adhesive may flow or drip from the adhesive line. If the viscosity of the adhesive is too high, spreading of the adhesive becomes difficult.

If the spacer is a mesh, it may be encapsulated in an adhesive that also bonds the two adjacent membranes.

FIG. 2 shows a spacer assembly 20 comprising a cation exchange membrane 200, a spacer 204, and an anion exchange membrane 202. The spacer 204 separates the cation exchange membrane 200 from the anion exchange membrane 202, and the spacer 204 may define a flow chamber and enhance mixing and mass transfer as the liquid stream flows from the inlet side 208 to the outlet side 210.

Fig. 3 shows first spacer assembly 30 and second spacer assembly 32 separated by spacer 304. The two components are bonded together with an adhesive 306 applied along two parallel edges perpendicular to the edges of the components that have been sealed. The spacer 304 sandwiched between the two components defines a flow passage for the second flow, which is in a direction perpendicular to the direction of flow through the two components, as indicated by the arrows.

The resulting membrane cell stack when compressed is shown in figure 4. As shown, the first spacer assembly 40 and the second spacer assembly 42 are secured to one another with the spacer 404 therebetween. The flow passages through each of the spacer assemblies 40 and 42 may extend in a first direction, while the flow passages through the chambers defined between the two spacer assemblies may extend in a second direction, as indicated by the arrows in FIG. 4.

The fluid flow in the first direction may be a dilute flow and the fluid flow in the second direction may be a concentrate flow. In some embodiments, the fluid flow in the first direction may be converted to a concentrate flow and the fluid flow in the second direction may be converted to a dilute flow using polarity inversion in which the applied electric field is reversed, thereby reversing the function of the flows.

A plurality of spacer assemblies separated by spacers may be secured together to form a stack of cell pairs or a membrane cell stack.

The electrical purification apparatus of the present disclosure may also include a housing enclosing the cell stack. At least a portion of the perimeter of the cell stack may be secured to the housing. A frame or support structure may be located between the housing and the cell stack for providing additional support to the cell stack. The frame may also include inlet and outlet manifolds that allow liquid to flow into and out of the cell stack. The frame and the cell stack may collectively provide an electrical purification apparatus modular unit. The electrical purification apparatus may also include a second modular unit secured within the housing. A spacer (e.g., a blocking spacer) may be located between the first modular unit and the second modular unit. The first electrode may be located at an end of the first modular unit opposite an end in communication with the second modular unit. The second electrode may be located at an end of the second modular unit opposite to an end communicating with the first modular unit.

The bracket assembly may be located between the housing and the frame of the first modular unit, the second modular unit, or both. The bracket assembly may provide support for the modular unit and provide secure attachment to the housing.

In one embodiment of the present disclosure, an electrical purification apparatus may be assembled by positioning a membrane cell stack in a housing or container. An end plate may be provided at each end of the cell stack. An adhesive may be applied to seal at least a portion of the perimeter of the cell stack to the inner wall of the housing.

Fig. 5 shows one embodiment of a cell stack 516 enclosed by a housing 518. The two end plates 512 are pulled together with tie bars 514. The tie rod 514 is isolated from fluid flow by a non-metallic sleeve. If the end plates 512 are metallic, a non-metallic end block 520 may be inserted between the cell stack 516 and the end plates 512 at each end. End block 520 supports the electrodes and isolates the liquid flow from the end plates. The ends of the tie rod sleeves are sealed against the end block 520 with O-rings. Alternatively, the end plate 520 may be non-metallic, and a separate end block may not be necessary. As shown in fig. 5, end plate 520 may be attached with bolts or screws 522 and nuts 524. As shown in fig. 6, end plate 620 may be attached using flange 649. As shown in FIG. 7, the end plates 720 may be attached using clips 728 (e.g., Victaulic type clips).

In some embodiments of the present disclosure, the tie bar may be located outside of the housing. In some other embodiments of the present disclosure, the end plate may be secured within the housing using a segmented ring or snap ring inserted into a groove at the end of the housing. The end plate may also be bonded to the housing using an adhesive.

For example, the metal end plate may be manufactured by machining or casting. The non-metallic end block or end plate can be manufactured, for example, by machining a piece of plastic or by injection molding.

Once the stack is positioned in the housing and the end plates/end plates are secured to the housing, an adhesive may be applied to seal the stack to the housing and isolate the inlet and outlet manifolds for the two streams from each other. The housing is first oriented with the longitudinal axis horizontal.

As described further below, the adhesive properties used to secure the membrane stack within the housing may be different than the adhesive properties used to secure the membranes to each other to form the cell stack. In order to fix the membrane stack in the housing, the viscosity of the adhesive must be low. Acceptable viscosity can be obtained by adding a reactive diluent to the mixed adhesive. The primary function of the diluent is to reduce the viscosity of the adhesive so that it is easier to mix or to improve coatability. Lower viscosity is also important to obtain a suitable adhesive, as lower viscosity allows more penetration into the porous matrix and allows wetting of the non-porous surface. The diluent may be diglycidyl ether, diglycidyl ether of diglycidyl phenyl, or the like.

The membrane cell flow chamber may be about 0.33 mm to 0.46 mm thick, and in some examples, the potting may be air gap free. The potting elastomer (adhesive) used to secure the cell stack to the housing should have a greater rigidity than the side seams used to secure the membranes to each other; this is possible because the potting must have sufficient mechanical strength to withstand the weight of the membrane stack. In certain embodiments, it is desirable if the potting does not deform under the feed flow pressure.

The housing is first oriented with the longitudinal axis horizontal. Figure 8 illustrates one method of applying adhesive 806 to secure the cell stack 816 within the housing 818. Housing 818 may be rotated so that the perimeter of cell stack 816 (in this embodiment, corners 830) are at the bottom. Low viscosity adhesive 806 is injected into the housing 818 and allowed to pool at the bottom. A sprue may be placed coincident with the perimeter of the cell stack 816, which may be incorporated into the housing 818 to facilitate injection of adhesive 806 into the housing 818 to seal the corners 830 of the cell stack 816 to the housing 818. After the adhesive 806 has set, the housing 818 may be rotated 90 until the next corner is at the bottom. The gluing step is repeated until all desired perimeters of the cell stack 816 are sealed or secured. Surface preparation to improve the sealing of the housing to the stack periphery may include techniques that can break the surface and increase the surface area to enhance adhesive bonding. For example, surface preparation may include chemical, mechanical, electrical, or thermal surface preparation, and combinations thereof. This may include, for example, chemical etching or mechanical roughening.

The housing may be manufactured, for example, by extrusion, to provide a geometry that facilitates securing the cell stack to the housing. For example, one or more recesses may be made in the housing so that the adhesive can be accommodated in a defined area for receiving the periphery of the cell stack. As shown in fig. 9, a housing 918 is provided having a scalloped recess 932, the scalloped recess 932 providing a reservoir for placement of the adhesive 906.

In another embodiment of the disclosure, a method of applying adhesive is provided that includes slowly rotating a housing in one direction while injecting a controlled amount of adhesive into the housing. The adhesive continues to flow to the lowest point and forms successive thin layers which can cure to form a sealing ring around the inner wall of the housing. The thickness of the ring can be increased by further adding glue.

In another embodiment of the disclosure, a method of applying adhesive is provided that includes rapidly rotating a housing in one direction while injecting a controlled amount of adhesive into the housing at one or more points. Centrifugal force may be used to push the adhesive against the inner wall of the housing and a sealing ring may be formed when the adhesive cures.

An embodiment of the present disclosure is shown in fig. 10 that provides a method that includes rotating housing 1018 in one direction while injecting a controlled amount of adhesive 1006 into the housing.

In another embodiment of the present disclosure, the electrical purification apparatus may be assembled by sealing a portion of the perimeter of the cell stack with an adhesive using a mold. The cell stack may be inserted into the housing and then compressed with end plates at each end of the cell stack. An adhesive may then be applied to seal the periphery of the cell stack to the inner wall of the housing.

As shown in fig. 11, the perimeter of the cell stack (in this example, corner 1130 of cell stack 1116) can be inserted into mold 1134. The low viscosity adhesive 1106 may be poured into a mold 1134 and allowed to cure. The stack is then rotated to seal the remainder of the perimeter, as shown in fig. 12, where an adhesive 1206 is shown in each corner 1230 of the cell stack 1216. In some examples, the mold is made of a material to which the adhesive does not adhere.

As shown in fig. 13, the cell stack 1316, with all four corners sealed, is inserted into the housing 1318 with a gap 1338 between the adhesive 1306 and an inner wall 1336 of the housing 1318. Gap 1338 is filled with additional glue, sealing cell stack 1316 to housing 1318 and preventing cross-leaks between flow manifolds.

In another embodiment shown in fig. 14, a membrane cell stack 1416 having a bracket assembly or corner bracket 1440 that can be fabricated, for example, using extrusion molding or injection molding, is used as a mold for potting and sealing the corners of the cell stack 1416. The corner brackets 1440 (and 1540) then act as an anchor to attach the stack to the housing 1542, as shown in fig. 15. Methods that may be used to secure the corner brackets to the housing include plastic welding techniques (e.g., ultrasonic welding). As shown in fig. 16, the housing 1542 (and 1642) is in turn inserted into the housing 1618, thereby eliminating the need to directly pot the stack assembly to the housing. Bracket assemblies or corner brackets may also be used to secure the modular unit to the housing.

In certain embodiments of the present disclosure, an electrical purification apparatus is provided that reduces or prevents inefficiencies due to greater power consumption. The electrical purification apparatus of the present disclosure may provide a multi-pass flow configuration for reducing or preventing low current efficiency. This multi-pass flow configuration may reduce bypass current or leakage of current through the flow manifold by eliminating or reducing a direct current path between the anode and cathode of the electrical purification apparatus. As shown in fig. 17, an electrical purification apparatus 50 is provided that includes a cathode 1744 and an anode 1746. A plurality of alternating anion exchange membranes 1748 and cation exchange membranes 1750 are present between cathode 1744 and anode 1746 to provide a series of alternating ion diluting compartments 1752 and ion concentrating compartments 1754. Blocking spacers 1756 may be located within one or more of the ion dilution chamber 1752 and the ion concentration chamber 1754 to redirect fluid flow and current flow through the electrical purification apparatus 50, as shown by the arrows in fig. 17.

Fig. 18 shows one example of a spacer that can be used as a blocking spacer in an electrical purification apparatus. The spacer may include a screen section 1858, a solid section 1860, and a sealing band 1862. As shown in fig. 19, a sealing tape 1862 may be bonded to an adjacent film using an adhesive. The sealing tape may improve the seal between the membrane and the spacer by providing a flat surface for adhesion. In certain examples, the spacer can be manufactured by injection molding, machining, thermal compression, or rapid prototyping.

The molded spacer may have a sufficient thickness so that the screen section may be molded. The thickness may be greater than the thickness of the screen spacer. Thus, the inter-film distance of a barrier chamber may be greater than the inter-film distance in an adjacent chamber, resulting in a higher resistance that is acceptable due to the limited number of barrier spacers.

The edge of the spacer at the solid portion may be fixed and sealed to the inner wall of the housing. The solid portion 1860 of the spacer may be sufficiently rigid to withstand a pressure differential on both sides. Structural features, such as ribs, may be added to the solid portion to increase the stiffness of the material.

As shown in fig. 19, a first spacer assembly 1964 and a second spacer assembly 1966 are provided. The blocking spacer 1956 is located between the first spacer assembly 1964 and the second spacer assembly 1966.

Fig. 20 illustrates one embodiment of an electrical purification apparatus of the present disclosure comprising a three-pass cross-flow electrodialysis apparatus. Cell stack 2016 is secured within housing 2018. Barrier spacers 2056 are located within the cell stack 2016 for redirecting the flow of fluid and current within the electrodialysis device, as indicated by the arrows in fig. 20.

In another embodiment, a portion of the perimeter of the cell stack and the perimeter of the blocking spacer are secured to the inner surface of the housing with an adhesive.

As shown in fig. 21, blocking spacer 2156 is provided having rounded edges 2168, which rounded edges 2168 form a recess for adhesive 2106 when spacer 2156 is inserted into the housing. As shown in fig. 22, the device can then be assembled by inserting multiple cell pairs 2216 and barrier spacers 2256 or spacers into the housing 2218 and then compressing this assembly with end plates and/or end blocks at both ends. Adhesive 2206 may be applied sequentially to a portion of the perimeter of the stack by potting.

Housing 2318 is then oriented with the axis vertical as shown in fig. 23A and edge 2368 is ready to receive adhesive. As shown in fig. 23B, adhesive 2306 is applied to the groove formed by edge 2368 on barrier spacer 2356, thereby sealing the spacer to housing 2318. For example, the adhesive may be injected through a small tube or conduit inserted through the end plate and/or end block.

In certain embodiments, other components (e.g., a gasket or an O-ring) may be used and positioned around the blocking spacer to help contain the liquid adhesive used to secure the spacer to the housing. In this embodiment, the adhesive, once cured, may be a primary seal. In another embodiment, other components (e.g., gaskets or O-rings) are designed to be the only seal between the blocking spacer and the housing, and adhesive 2206 (see fig. 22) located at only a portion of the perimeter of the cell stack may be used. This may simplify the modular unit assembly by reducing or eliminating the need to seal the edges of the blocking spacer to the housing with an adhesive material.

In another embodiment, a stack of cell pairs having a diluting compartment and a concentrating compartment in a single pass flow configuration is first sealed in a section of a cylindrical housing to form a modular unit. The cells may then be connected together with the blocking spacers in between to form a multi-pass configuration. One advantage of this approach is that the stack can be sealed to the section of the housing with adhesive only at a portion of the perimeter (e.g., the corners). The blocking spacer does not have to be sealed to the inner wall of the housing; instead, the blocking spacer is located between the modular units and sealed between the ends.

Fig. 24A shows, for example, first modular unit 2470 and second modular unit 2472 with flanges 2474 at the ends and blocking spacers 2456 between the units. In fig. 24B, first modular unit 2470 and second modular unit 2472 are secured to each other. Flanges 2474 of first modular unit 2470 and second modular unit 2472 can be secured together. In some examples, flanges 2474 of first modular unit 2470 and second modular unit 2472 can be bolted together.

Figure 25 shows another embodiment of a blocking spacer with a screen portion 2558, a solid portion 2560 and a sealing strip 2562. The blocking spacer may be molded with a circular frame 2576 that is sealed between the flanges with an adhesive or gasket. Alternatively, the frame may be molded from a thermoplastic material, thereby eliminating the need for adhesives or gaskets. Other methods for fabricating the blocking spacer will be apparent to those skilled in the art.

Alternatively, clamps, tie rods, or other fastening techniques may be utilized to connect the modular units together. The design of the blocking spacer may be modified accordingly to accommodate the selected fixation technique.

In some embodiments of the present disclosure, a method for preparing a cell stack is provided. The first spacer assembly may be prepared by securing the first ion exchange membrane to the second ion exchange membrane at a first portion of the perimeter. At the second portions of the first and second ion exchange membranes, the perimeter may be folded to provide an end fold. The spacer may be disposed between the first ion exchange membrane and the second ion exchange membrane. The second spacer assembly may be similarly prepared. The end folds of the first spacer assembly may be aligned with the end folds of the second spacer assembly to secure the end folds of the second ion exchange membrane to the end folds of the ion exchange membrane of the second spacer assembly. These end folds can then be collapsed and the spacer can be positioned between the spacer assemblies. When the spacer assemblies are compressed, a chamber is formed to provide fluid flow between the spacer assemblies in a direction different from the fluid flow within each of the first and second spacer assemblies.

As shown in fig. 26, a first spacer assembly may be prepared by securing a first anion exchange membrane 2602 to the first cation exchange membrane 2600 at a first portion of the perimeter. In this example, the first portion of the perimeter is secured with thermal bonding 2678. At the second portions of the first anion exchange membrane and the first cation exchange membrane, the perimeter can be folded to provide end folds 2680. Spacer 2604 can be disposed between first anion exchange membrane 2602 and first cation exchange membrane 2600.

The second spacer assembly may be similarly prepared. As shown in fig. 27, the end folds 2780 of the first spacer assembly may be aligned with and overlap the end folds 2784 of the second spacer assembly, thereby securing the end folds of the first cation exchange membrane to the end folds of the anion exchange membrane of the second spacer assembly. The overlapping portions of the end folds may be secured using thermal bonding, adhesives, or mechanical techniques. As shown in fig. 28, the end folds can then be collapsed, and the spacer 2804 can be positioned between the spacer assemblies. When the spacer assemblies are compressed, a chamber is formed to provide fluid flow 2986 between the spacer assemblies in a different direction than the fluid flow 2988 within each of the first and second spacer assemblies, as shown by the arrows in fig. 29.

By utilizing a thermal bonding technique to prepare the spacer assembly and the resulting cell stack, a process is provided that may allow for simplified assembly and may provide for faster overall assembly times of the electrical purification apparatus. The narrow thermal seal provides a larger flow channel, which may result in higher membrane utilization, which may increase the overall efficiency of the electrical purification apparatus. In certain embodiments employing thermal bonding, additional reinforcing strips of polymeric material (e.g., polypropylene or polyethylene) may be used to reinforce the thermal bonding zone and provide a more robust and durable seal. By thermally bonding the films prior to collapsing and compressing the films, it may also help to simplify assembly as there is more room for suitable bonding equipment and devices to assist in the bonding process. Thermal bonding techniques also prevent leaks in the film stack. This process may also reduce the compressive force on the membrane spacers to maintain cell stack integrity, resulting in a lower pressure drop across the modular unit.

In some embodiments, the ion exchange membranes and spacers may be secured in the cell stack using an adhesive. The adhesives that may be used to prepare the cell stack may have particular characteristics or properties that allow for proper sealing of the components of the cell stack and securing the cell stack within the electrical purification apparatus housing. These properties may include the viscosity, gel time, cure temperature, and elastic properties of the adhesive. It has been found that by modifying the properties of the adhesive, the strength of the bond between the membrane stack and the housing can be increased and leakage within the electrical purification apparatus reduced or eliminated.

In some cases, epoxy or epoxy-based materials or polyurethane-based materials may be used. This is because their thermal, mechanical and chemical properties may allow them to provide suitable sealing of the membranes to each other and to the cell stack to the housing.

The epoxy or epoxy-based material may include a resin and a curing agent. The resin may need to be crosslinked in order to provide a suitable seal to the membrane or to the housing. This crosslinking may be achieved by chemically reacting the resin with a suitable curing agent. The curing agent may be selected from aliphatic amines, amidoamines (amidoamines), alicyclic amines, and aromatic amines. The curing agent may provide specific properties to the adhesive including, but not limited to, viscosity, shelf life, cure time, permeability, wetting ability, mechanical strength, and chemical resistance after curing.

Polyurethanes or polyurethane-based materials can be made by the polymeric addition reaction of isocyanides with polyols (polyols) in the presence of a catalyst. This reaction can provide a polymer containing a urethane chain-RNHCOOR'.

In some embodiments, when an adhesive suitable for securing the films to each other is required, it is desirable that the adhesive remain to some extent on the predetermined adhesive line or sealing strip. If, for example, the viscosity of the adhesive is too low, the adhesive may run off or drip from the adhesive line or the sealing tape. If the adhesive is too tacky, the spreading of the adhesive becomes too difficult.

In certain embodiments, it is desirable to use an adhesive that has a similar thermal expansion as the films to secure the films to one another. This may prevent or reduce cracks or wrinkles at the film-adhesive interface. To determine a suitable adhesive for electrical purification device applications, the concentration of the amine curing agent can be varied. For example, aliphatic amines have a straight carbon backbone, which can provide a high degree of flexibility for thermal expansion. The use of this type of curing agent may allow the side seam to expand with the film. Cycloaliphatic and aromatic amine curatives have aromatic rings in their backbone, which can provide rigid elastomeric properties.

In certain embodiments of the present disclosure, the adhesive that may be used to secure the films to each other may have a viscosity in the range of from about 1000 to about 45,000 cps at ambient temperature. This may provide a gel time in the range of from about 15 minutes to about 30 minutes. The adhesive may have a shore D hardness ranging from about 30 to about 70 at ambient temperature.

The adhesive may be applied by any suitable means, and may be applied by an automated or manual step. The seam formed by the adhesive may have a width in the range of about 0.25 inches to about 1.5 inches and an adhesive thickness in the range of about 20 mils to about 50 mils. The adhesive may be cured by using ultraviolet light, ambient temperature, accelerated temperature, and the like.

The adhesive used to secure the membrane cell stack to the housing may have a low viscosity, which may be achieved by adding a reactive diluent to the mixed adhesive. By adding a diluent, a lower viscosity adhesive may be obtained and may allow for easier application of the adhesive. This lower viscosity may also provide greater permeability to the porous substrate and better wetting on the non-porous surface. In certain examples, the diluent may be selected from diglycidyl ethers, diglycidyl ethers of diglycidyl phenyl groups, and combinations thereof.

The adhesive used to secure the cell stack to the housing may be more rigid than the adhesive used to secure the membranes to each other. The adhesive used to secure the cell stack to the housing can be formulated to have sufficient mechanical strength to withstand the weight of the membrane cell stack and to not deform under the flow pressure.

In certain embodiments of the present disclosure, the adhesive used to secure the cell stack to the housing may have a viscosity ranging from about 300 cps to 2000 cps at ambient temperature. The gel time of the adhesive may range from about 30 minutes to about 60 minutes. The adhesive may have a shore D hardness at ambient temperature in the range of about 45 to 80.

The housing in which the membrane cell stack is positioned and secured to provide an electrochemical purification device may be made of any suitable material that allows and retains fluids and electrical currents within the device. For example, the housing or shells may be made of polysulfone, polyvinyl chloride, polycarbonate or epoxy impregnated fiberglass. The material for the housing may be made by an extrusion process, injection molding, or other process that generally provides a dense structure with a generally smooth interior. To enhance the adhesive bond between the housing and the membrane cell stack (which may fail due to the force of the continuous fluid flow), a portion of the inner surface of the housing where the membrane cell stack is secured is treated or modified. Surface preparation for improving the seal of the housing to the stack periphery may include techniques that can break the surface and increase the surface area to enhance adhesive bonding. For example, surface preparation may include chemical, mechanical, electrical, or thermal surface preparation, and combinations thereof. This may include, for example, chemical etching or mechanical roughening.

In certain embodiments, an adhesive injection port in the housing is used to help deliver adhesive to a desired area within the housing to secure the membrane cell stack to the housing. The adhesive may be introduced into the housing using one or more adhesive injection ports. More than one adhesive injection port may be used at each fixation point in the housing. In certain embodiments, three adhesive injection ports may be provided in a particular arrangement to distribute adhesive to a fixed point in an appropriate manner. The adhesive injection ports may be located in a straight line or may be spread out in a particular design or pattern to achieve the desired adhesive delivery. In examples where a low viscosity adhesive is used, the adhesive may penetrate into the channels of the membrane cell stack to enhance the bond between the membrane cell stack and the housing. By injecting the adhesive in this manner, the amount of adhesive used and the exotherm generated by the adhesive can be monitored.

In certain embodiments of the present disclosure, mechanical sealing techniques may be utilized to secure the membranes to each other and to secure the membranes to the spacers within the membrane cell stack. The sealing may be achieved by forming ridges or grooves on at least one of the membrane and the spacer used in the electrical purification apparatus. The ridges or grooves on the first membrane or spacer may mate with the ridges or grooves on the second membrane or spacer. The ridges or grooves on the first membrane or spacer may interlock with the ridges or grooves on the second membrane or spacer. For example, the ridges or grooves on the first membrane or spacer may be male ridges or fittings that mate with ridges or grooves (which may be female ridges or fittings) on the second membrane or spacer. An ion exchange membrane (e.g., a cation exchange membrane or an anion exchange membrane) may be positioned and secured between the first spacer and the second spacer. In certain embodiments, once a series of spacers and ion exchange membranes have been assembled to form a plurality of concentration and dilution flow chambers, the chambers may be filled with a resin (e.g., in the form of a resin slurry or resin suspension).

Fig. 30 shows an example of an injection molded diluent spacer 3004 with a groove 3090 for mating with a seal on both surfaces of spacer 3004. One end of each flow cell 3092 is closed except for opening 3094, which opening 3094 holds ion exchange resin beads but allows fluid flow. The other end 3096 of the spacer 3004 may be opened to fill the resin. There may be a slot 3098 at one end for receiving a resin retaining plate. The concentrated spacer was also manufactured in the same manner. In some examples, the concentrating spacer may be thinner than the diluting spacer because, in some embodiments, the concentration flow may be lower than the flow through the diluting compartments.

Fig. 31 shows a cross-sectional view through the stack of spacers 3104 and the cation exchange membrane 3100 and anion exchange membrane 3102 prior to assembly. The female feature 3101 on the first spacer 3104a can mate with the male feature 3103 on the second spacer 3104 b. The male feature 3103 on the second spacer 3104b may also mate with the female feature 3101 on the third spacer 3104 c.

To enhance ion transport through the resin beads and membrane, it is desirable to closely pack the resin beads. This is particularly advantageous in dilution chambers in ultrapure water applications. It has been found that there are many possible ways to increase the packing density. For example, the resin may be soaked in a concentrated salt solution (e.g., sodium chloride) and then grouted into the chamber. During operation of the electrical purification apparatus, the resin in the dilution chamber expands as the dilution stream is deionized. These resins can also be soaked in concentrated salt solutions (e.g., sodium chloride) and then dried. These resins can then be suspended in a stream of air and then blown into a chamber. During operation, the resins in the diluting and concentrating compartments will expand when they are exposed to the fluid, and the resins in the diluting compartments will expand further when the diluting stream is deionized. In another example, the concentrating compartment may be filled before the diluting compartment. The membrane will be allowed to bulge into the dilution chamber and then fill the dilution chamber. The expansion of the resin in the dilution chamber during operation may be limited by the resin filled into the concentration chamber, thereby increasing the packing density.

Fig. 32 shows a cross-sectional view of a portion of an assembled stack of spacers 3204 (including 3204a, 3204b, and 3204 c) and membranes, and a detailed view of the mechanical seal interlock. As shown in the detail view, once the stack with the desired number of cell pairs is assembled, chamber 3292 can be filled with resin. A resin slurry in a fluid is pumped into the chamber. The resin may be held in an opening 3294 at the bottom of the chamber while the resin carrier fluid flows through. When the chamber is full, the slotted plate is slid into place to hold the resin in the chamber. The stack is then rotated 90 ° and the dilution chamber is filled with resin in a similar manner.

Fig. 33 shows a portion of a membrane cell stack 3305 with a resin retaining plate 3307 in place. Membrane stack 3305 may be secured in the housing at specific points along the perimeter of stack 3305. For example, the cell stack can be secured at one or more corners 3330 of cell stack 3305.

In another embodiment, the membrane is sealed to the spacer with an overmolded thermoplastic rubber (TPR) seal. After assembly and compression of the stack of spacers and membranes, the concentrate and dilute flow chambers are filled with resin. Figure 34 shows a dilute spacer 3404 with an edge 3407 and an overmolded seal 3409. An overmold seal may be present on both faces of the spacer. The concentrated spacer may be similarly manufactured. In certain examples, the concentrated spacer may be configured to be thinner than the dilute spacer, and may not include an overmolded seal.

Fig. 35 is a cross-sectional view through a portion of a stack of spacers and membranes including a concentrate spacer 3511 and a dilute spacer 3513. Openings 3594 retain resin within chamber 3592, and openings or slots 3598 at opposite ends of chamber 3592 allow for filling with resin. In this particular embodiment, a circular edge 3507 is shown, but other edge shapes (e.g., rectangular, square, or polygonal) may be employed, so long as the resulting cell stack is sufficiently secured to the housing. In some embodiments, the edge 3507 may eliminate the need for a housing. Radial overmold seals 3509 may separate dilute and concentrate inlet/outlet manifolds, thus eliminating the need for corner fixings or potting. Prior to adding the resin to the stack, the stack may be compressed to seal the membrane and spacer together. This can be achieved using, for example, temporary tie bars or clamps.

Fig. 36 is a sectional view showing the resin retaining plate 3607 in place after the dilution chamber 3615 is filled with resin.

In certain embodiments, the seal formed by the overmolded seal and the fit formed by the male and female features may collectively be used to provide a fixed membrane cell stack. The membrane may be sealed to the spacer with male and female features, while the radial overmold seal and the seal in the rim may seal the dilute spacer to the concentrated spacer. In this embodiment, it may not be necessary to use a housing or corner seals to seal the cell stack to the housing.

In certain embodiments, an injection molded spacer 3704 is provided that includes a screen region 3725, as shown in fig. 37. The figure shows a fluid flow direction 3727. Openings are provided in two opposing edges 3729 and 3731. The openings may be formed by wires that shrink before being removed from the mold.

Fig. 38A and 38B show details of the opening in edge 3829 as discussed with respect to fig. 37, e.g., at 3833. Fig. 38A and 38B also illustrate a male feature 3803 that may interlock with female feature 3801.

Dashed parting lines are shown in fig. 38B. The spacers may be molded with a set of strands above the parting line 3835 of the mold and a set of strands below the parting line 3835. The strands of the screen spacer as shown in fig. 38B have a semi-circular cross-section and the two sets of strands are oriented perpendicular to each other. Fluid mixing may be facilitated and/or pressure drop may be reduced by varying the cross-sectional shape, orientation, and frequency of the strands. Ribs or baffles may be molded into the spacer to form flow channels and improve flow distribution.

In certain embodiments, male and female features are molded at the top and bottom of the edge including the inlet and outlet openings 3833, respectively.

The choice of material for the spacer depends on its ability to be molded to thin walls and small dimensions, such as on the order of about 0.060 inches (1.5 mm) or less. The material may also have the ability to be molded with small holes, preferably about 0.030 inches (0.75 mm) or less. The material may have suitable elasticity to allow proper interlocking of the male and female features and may have chemical compatibility with the fluid to be purified.

Fig. 39 shows a portion of a stack of spacers and membranes. As shown in the figures, male feature 3903 interlocks with female feature 3901. Similarly, in fig. 40, the male feature 4003 interlocks with the female feature 4001. The cation exchange membrane 4000 and the anion exchange membrane 4002 are fixed between the spacers. The spacer 4037 for the first flow seals the edge of the membrane bound for the second flow, and the spacer 4039 for the second flow seals the edge of the membrane bound for the first flow.

In certain embodiments of the present disclosure, the flow rate within the chamber may be adjusted, redistributed, or redirected so as to provide greater contact of the fluid with the membrane surface within the chamber. The chamber may be constructed and arranged to redistribute the fluid flow within the chamber. The chamber may have obstructions, tabs, protrusions, flanges, or baffles that may provide structure to redistribute the flow through the chamber. The obstructions, projections, protrusions, flanges, or baffles may be formed as part of the ion exchange membrane (spacer) or may be other separate structures disposed within the chamber. The obstructions, projections, protrusions, flanges or baffles may be formed by providing extensions from an adhesive that can secure the ion exchange membranes to each other. The spacers may be impregnated with a thermoplastic rubber to form protrusions that may be bonded to the adjacent membrane with an adhesive. The thermoplastic rubber may be applied to the spacer using processes such as hot pressing or rotary screen printing. The chamber may or may not contain ion exchange resin.

As shown in fig. 41, a first ion exchange membrane 4151 and a second ion exchange membrane 4153 are shown with a first spacer 4155 and a second spacer 4157 adjacent thereto. The first flow 4159 is shown flowing in a direction parallel to the flow of the second flow 4161 because of the second spacer 4157 with baffles, which redistributes the flow, starting from the inlet 4163 of the spacer 4157, flowing around the first baffle 4165 and around the second baffle 4167 and flowing through the outlet 4169.

As shown in fig. 42, a first ion exchange membrane 4251 and a second ion exchange membrane 4253 are shown, with a first spacer 4255 and a second spacer 4257 adjacent thereto. The first flow 4259 is shown flowing in a direction perpendicular to the flow of the second flow 4261 because of the second spacer 4257 having baffles, which redistribute the flow, starting at the inlet 4263 of the spacer 4257, flowing around the first baffle 4265 and around the second baffle 4267 and flowing through the outlet 4269.

Fig. 43 and 44 show other embodiments of chambers for two flows formed by injection molded spacers. In FIG. 43, the flow path of the second flow 4361 can be concurrent or counter-current to the first flow 4359. In fig. 44, the flow path of the second flow 4461 may be perpendicular to the first flow 4459. The solid portion of the selected spacer may be bonded to the adjacent membrane with an adhesive. Alternatively, the membrane may be thermally bonded to the spacer by, for example, ultrasonic, vibration or laser welding. As shown in these figures, the dashed arrows indicate the flow in the inlet and outlet manifolds for the second stream. These manifolds do not depend on the inlet and outlet of the flow chamber for the second flow. Thus, leakage current along the manifold between the anode and cathode is expected to be reduced.

In some embodiments of the present disclosure, a method of providing a source of drinking water is provided. In certain embodiments, a method of simplifying the production of potable water from seawater is provided. The method may include providing an electrical purification apparatus including a cell stack. The method may further comprise fluidly connecting the seawater feed stream to an inlet of an electrical purification apparatus. The method may further comprise fluidly connecting an outlet of the electrical purification apparatus to a drinking point. The seawater or estuary water may have a total dissolved solids concentration in the range of about 10,000 to about 45,000 ppm. In certain examples, the seawater or estuary water may have a total dissolved solids concentration of about 35,000 ppm.

In this embodiment, the cell stack may include alternating ion diluting compartments and ion concentrating compartments. Each ion dilution chamber may be constructed and arranged to provide a fluid flow in a first direction. Each ion concentrating chamber may be constructed and arranged to provide fluid flow in a second direction different from the first direction, as described above. Further, each of the ion concentrating and diluting compartments may be constructed and arranged to provide a predetermined percentage of surface area or membrane utilization for fluid contact for each alternating ion diluting and depleting compartment. As noted above, it has been found that greater membrane utilization provides greater efficiency in the operation of an electrical purification apparatus. In certain embodiments, the achievable membrane utilization is greater than 65%. In other embodiments, the achievable membrane utilization is greater than 75%. In certain other embodiments, the achievable membrane utilization may be greater than 85%.

At least one of the ion diluting compartment and the ion concentrating compartment may include a spacer. The spacer may be a blocking spacer. This allows the seawater feed to pass through the electrical purification apparatus in multiple stages or passes to provide a source of potable water.

The first fluid flow direction and the second fluid flow direction may be selected and provided by the configuration and arrangement of the chambers. The first fluid flow direction serves as a direction extending along the 0 ° axis, and the second fluid flow direction may extend in a direction of any angle greater than 0 degrees and less than 360 °. In certain embodiments of the present disclosure, the second fluid flow channel may extend at a 90 ° angle or in a direction perpendicular to the first fluid flow channel. In other embodiments, the second fluid flow passage may extend in a direction that is 180 ° from the first fluid flow passage.

The method may further include redistributing the fluid in at least one of the alternating ion diluting compartments and ion concentrating compartments. One or more of the chambers may be constructed and arranged to redistribute or redirect the fluid flow. This may be accomplished by using a particular spacer or membrane that defines a chamber that may provide a configuration that redistributes the fluid flow, as described above.

The electrical purification apparatus may also include a housing enclosing the cell stack. At least a portion of the perimeter of the cell stack can be secured to the housing. The electrical purification apparatus may also include a frame or support structure located between the housing and the cell stack. The frame may be adjacent to or connected to the cell stack to provide a modular unit. The electrical purification apparatus may also include a second modular unit, which may be secured within the housing. The second modular unit may be secured within the housing such that the ion exchange membrane of the first modular unit is adjacent to the ion exchange membrane of the second modular unit.

The method of providing a source of potable water may include redirecting at least one of an electrical current and a fluid flow between the first modular unit and the second modular unit. This may be accomplished, for example, by providing a blocking spacer between the first modular unit and the second modular unit.

A bracket assembly may be positioned between the frame and the housing to secure the modular unit to the housing.

Other types of feedwater including different total dissolved solids concentrations may be treated using the apparatus and methods of the present disclosure. For example, brackish water having a total dissolved solids content in the range of about 1000 ppm to about 10,000 ppm can be treated to produce potable water. Concentrated brine having a total dissolved solids content in the range of about 50,000 ppm to about 150,000 ppm may be treated to produce potable water. In some embodiments, concentrated brine having a total dissolved solids content in the range of about 50,000 ppm to about 150,000 ppm may be processed to produce water having a lower total dissolved solids content for disposal to a body of water such as the ocean, for example.

Although exemplary embodiments of the present disclosure have been disclosed, many modifications, additions, and deletions may be made therein without departing from the spirit and scope of the disclosure and its equivalents as set forth in the appended claims.

Those skilled in the art will readily appreciate that the various parameters and configurations described herein are intended to be exemplary and that the actual parameters and configurations will depend on the particular application to which the electrical purification apparatus and methods of the present disclosure are applied. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. For example, one skilled in the art will recognize that an apparatus and its components according to the present disclosure may also comprise a network of systems, or be components of a water purification or treatment system. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the electrical purification apparatus and methods of the present disclosure may be practiced otherwise than as specifically described. The apparatus and methods of the present invention are directed to each individual feature or method described herein. In addition, any combination of two or more such features, devices, or methods, if such features, devices, or methods are in accordance with one another, is included within the scope of the present disclosure.

For example, the housing may have any suitable geometry such that one or more membrane cell stacks or modular units may be secured within. For example, the housing may be cylindrical, polygonal, square, or rectangular. Any suitable geometry is acceptable in terms of membrane cell stacks and modular units, as long as the cell stack or modular unit can be secured to the housing. For example, the membrane or spacer may have a rectangular shape. In some embodiments, the housing may not be required. The geometry of the membranes and spacers may be any suitable geometry such that the membranes and spacers may be secured within the cell stack. In certain embodiments, it may be desirable to have a certain number of corners or vertices on the cell stack. For example, it may be desirable to have three or more corners or vertices to secure the cell stack to the housing. In certain embodiments, the geometry of any of the housing, cell stack, membrane, and spacer can be selected to accommodate operating parameters of the electrical purification apparatus. For example, the spacer may be asymmetric to accommodate the difference in flow rate between the dilute and concentrate streams.

In addition, it is to be appreciated various alterations, modifications, and improvements will be apparent to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the disclosure. For example, existing devices may be modified to apply or incorporate one or more aspects of the present disclosure. Thus, in some cases, the devices and methods may involve including electrical purification devices in existing equipment. Accordingly, the foregoing description and drawings are by way of example only. Furthermore, the description in the drawings does not limit the disclosure to the specifically illustrated illustrations.

The term "plurality" as used herein refers to two or more items or components. The terms "comprising," including, "" carrying, "" having, "" containing, "and" involving, "whether in the written description or in the claims and the like, are open-ended terms, i.e., to mean" including, but not limited to. Thus, use of such terms is intended to encompass the items listed thereafter and equivalents thereof, as well as additional items. For the purposes of the claims, the only transitions "consisting of … …" and "consisting essentially of … …" are closed or semi-closed transitions, respectively. The use of ordinal terms such as "first," "second," "third," etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which steps of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

Claims (19)

1. A cell stack for an electrical purification apparatus, comprising:

a plurality of alternating ion depleting and ion concentrating compartments, each of said ion depleting compartments having an inlet and an outlet providing a diluting fluid flow in a first direction and each of said ion concentrating compartments having an inlet and an outlet providing a concentrating fluid flow in a second direction different from said first direction;

a blocking spacer located in the cell stack and constructed and arranged to change a direction of at least one of a dilute fluid flow and a concentrated fluid flow through the cell stack.

2. The cell stack of claim 1, wherein the blocking spacer is constructed and arranged to reduce current inefficiencies within the electrical purification apparatus.

3. The cell stack of claim 1, wherein the blocking spacer is constructed and arranged to redirect current within the cell stack.

4. The cell stack of claim 1, wherein at least one of the plurality of ion depleting compartments and ion concentrating compartments comprises a flow redistributor.

5. The cell stack of claim 1, further comprising a housing enclosing the cell stack, at least a portion of the perimeter of the cell stack being secured to the housing.

6. The cell stack of claim 5, further comprising a frame positioned between the housing and the cell stack to provide a first modular unit.

7. The cell stack of claim 6, further comprising a second modular unit secured within said housing.

8. The cell stack of claim 7, further comprising a blocking spacer between said first modular unit and said second modular unit.

9. The cell stack of claim 6, further comprising a rack assembly positioned between said frame and said housing.

10. The cell stack of claim 1, wherein the first direction is perpendicular to the second direction.

11. An electrical purification apparatus comprising:

a cell stack comprising alternating ion diluting compartments and ion concentrating compartments, each of the ion diluting compartments being constructed and arranged to provide fluid flow in a first direction and each of the ion concentrating compartments being constructed and arranged to provide fluid flow in a second direction different from the first direction;

a first electrode adjacent to an anion exchange membrane at a first end of the cell stack;

a second electrode adjacent to a cathode exchange membrane at a second end of the cell stack;

a blocking spacer located within the cell stack and constructed and arranged to redirect at least one of a dilute fluid stream and a concentrated fluid stream through the electrical purification apparatus and prevent a direct current path between the first electrode and the second electrode.

12. The electrical purification apparatus of claim 11, wherein the blocking spacer is constructed and arranged to reduce current inefficiencies within the electrical purification apparatus.

13. The electrical purification apparatus of claim 11, wherein at least one of the ion dilution compartment and the ion concentration compartment comprises a flow redistributor.

14. The electrical purification apparatus of claim 11, further comprising a housing enclosing the cell stack, at least a portion of a perimeter of the cell stack being secured to the housing.

15. The electrical purification apparatus of claim 14, further comprising a frame positioned between the housing and the cell stack to provide a first modular unit.

16. The electrical purification apparatus of claim 15, further comprising a second modular unit secured within the housing.

17. The electrical purification apparatus of claim 16, further comprising a blocking spacer located between the first modular unit and the second modular unit.

18. The electrical purification apparatus of claim 15, further comprising a bracket assembly positioned between the frame and the housing.

19. The cell stack of claim 11, wherein the first direction is perpendicular to the second direction.